The dissociative adsorption of oxygen on Mo(001) has been studied using low energy (500-1000 eV) Li+, K+ and He+ ion scattering. Oxygen adsorption affects the energy and angular distributions of scattered ions, and also the intensity of scattered ions changes in a manner which is dependent upon the type of ion used. The scattered ion intensities are examined as a function of oxygen exposure and compared for each type of ion for the same surface structure and under identical scattering geometry. The He+ intensity drops very sharply with increasing oxygen exposure, decreasing by a factor of 10 with ≤ 2 L exposure for all azimuthal angles of incidence. The Li+ intensity in all azimuths exhibits an initial decrease followed by a large increase and ultimately a decrease again as oxygen exposure increases. The K+ intensity, while decreasing with exposure for incidence in the  azimuth, is relatively unaffected by low oxygen exposure in the  azimuth. These contrasting dependencies are discussed and explained as manifestations of different neutralization mechanisms occuring in each case.
ASJC Scopus subject areas
- Nuclear and High Energy Physics